Do this first: " in SketchUp, select View > Face Style > Monochrome to see whether the back sides of a any faces point outward. By default, the face fronts are white and face backs are dark gray. To reverse a face, context-click it and select Reverse Faces. If you use Solid Inspector 2, the extension can find and fix the reversed faces for you." In essence you're making sure that all your faces face outward. Inward facing faces would be invisible unless the camera is inside the model. Check your output in Three.
Then if that doesn't work, try making all the materials double sided in Three.js:
object.traverse(function(node){
if(node instanceof THREE.Mesh){
node.material.side = THREE.DoubleSide;
}
})
If that doesn't work, I have had issues with fragmented export from Sketchup2017 just recently. Save your skp file in a folder that is not on your desktop or a network folder. Close the file, close sketchup, reboot your machine. Reopen Sketchup, open the skip file. Select all objects and copy. Open a new project and paste the objects. Save as a new skp file, Select everything you want to see in your obj or dae file and group them. Choose export to obj or dae. Test in Three.js.
If none of those things work, then I would try a different model to see if there isn't something wrong with the Warehouse file.